Electroplating process.



. case 1s usually made in a FRANCIS J. MeELI-IONE, or JERSEY cITY, NEWJERSEY.

ELEGTROPLATING PROCESS.

No Drawing.

Specification of Letters Patent.

Patented Feb. 20, 1912.

Application filed. March 26, 1908. Serial No. 423,358.

Process, of which the following is a full,

clear, and exact description.

This invention relates to electroplating or electrotyping. v

In preparing an electrotype, a mold or plastic material and covered withgraphite or black lead to render the same conductive when placed in theplating bath. It is found, however, that it is expedient to increase theconductivity of the raphite coat in some manner,

commence at once.

so that the ormation of the deposit will It is also found that with thegraphite used for this purpose, there is a tendency to form pin holes orunplated spots on the face of the case. It has been customaryheretofore, to treat the leaded cases with sulfate of copper and ironfilings, to increase the conductivity so that plating willcommence atonce when the case is placed in the bath. This practice tends to scratchthe case, which produces defective electrotypes. Electrotypes are alsomade on a soft metal, such as lead, by im.

pressing its face to make a mold. Graphite is applied to molds of thiskind to form a dividing coat which will enable the depositedelectroplate to be relieved, or removed from the metal body of the mold.

The object of this invention is to provide a process for improving theconductivity of w the coat of the case or mold and to overcome thetendencies inthe graphite to produce pin-holes and similar defects.

The invention consists in the process to be I described more fullyhereinafter and particularly set forth in the claims.

In carrying out my process, I prepare a solution of pyrogallic acid bymixing about two hundred grains to a gallon of water.

This acid is an organic acid and an oxygen acidof the carbocyclic group.While I prefer to use pyrogallic acid, I may use tannic, gallotannicacid or gallic acid for my purpose. With this solution I imx about eightpounds of graphite and stir the mixture until the graphite becomesthoroughly Wet and pasty. I then pour in large quantities of water andstir thoroughly to wash the acid from the graphite. I then collect thegraphite by decanting and filtration. The graphite after washing, isthoroughly dried and is then put on the face of the mold in a drycondition in any of the well known ways, suchas by means of a brush orblast. If desired, the graphite may be applied to the mold without beingdried after washing, according to the wet process described in myapliYcation Serial No. 373,046, filed May 11, 190

' The treatment of the graphite with the acid as described above, seemsto change its condition advantageously,rendering 1t more conductive andovercoming its normal tendency to form bubbles of oxygen or air whichmake pinholes or similar defects in the plate.

Having thus described my invention, I claim as new anddesire to secureby Letters Patent:

1. The process which comprises treating graphite with an organic acidprior to applying said graphite to a mold, washing thereafter, andelectroplating thereafter.

2. The process which comprises treating graphite with an organic acid,drying the graphite, applying the graphite to a mold, and electroplatingthe said mold thereafter.

3. The process which comprises treating graphite with an organic acid,washing the graphite after treatment with said acid, applying thegraphite to the mold and electroplating thereafter.

4. The process which comprises treating graphite with an acid of thecarbocyclic group, washing the acid from said graphite, applying thegraphite to a mold, and electroplating said mold.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

FRANCIS J. MCELHONE.

Witnesses:

F. D. AMMEN, EVERARD B. MARSHALL.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents,

Washington, I). G.

